Marion Cotillard, the Oscar-winning French actor, has perfect recall of the first time she met Matthias Schoenaerts: "I was like, Wow. Wowww! What is that?" Now I'm sitting opposite the 34-year-old from Antwerp, it's clear why she was so awed. He's almost 6ft 2in, clear-eyed, and if you were told he was Ryan Gosling's rougher, tougher elder brother, you'd believe it. He looks sent from casting heaven to dominate Hollywood movies for the next decade. Or, as Cotillard went on, "Amazing actor, super sexy, charismatic … a real man."

If you were only familiar with the Belgian from his work on screen, then this effusive description might be confusing. His calling card to date has been brutish, unlovable outsiders with varying personality disorders. He gained 30 kgs of hard-pack muscle to play a childlike cattle farmer with a steroid addiction in Bullhead, one of 2012's foreign-language Oscar nominees. He spent 18 months in training for the role and admits that the astonishing performance almost sent him insane.

Schoenaerts bulked up again for his new film, Rust and Bone, but this time he hit fast-food joints, not the gym. His character, Ali, is a nightclub bouncer and backyard brawler who falls into an unorthodox relationship with an orca trainer (Cotillard) who lost her legs in an accident at a marine park. It's a schmaltzy idea, adapted from a short story by Craig Davidson, but in the hands of the excellent leads it becomes strangely affecting, a deserving winner of the best film award at the London film festival.

"Rust and Bone could have been pathetic," accepts Schoenaerts, his added weight long gone. "It could have been too dark or too pessimistic but it's light in a weird way. It has a sparkle to it."

In person, he's the antithesis of his thuggish screen persona: smart and affable, his English precise. "I don't know what draws me to those roles," he says. "I just love stuff that is fucked-up! That's the way it is."

America has taken notice and next year we will see Schoenaerts reprising his role in The Loft, the most successful Flemish film ever, and appearing in Blood Ties, alongside Mila Kunis, Clive Owen and Cotillard again. Don't expect it to stop there; he let slip that he'd had a meeting with the director Michael Mann to discuss working together.

Schoenaerts has heard the comparisons to Gosling and – for now at least – he's finding them amusing. "My girlfriend says it, as well," he replies, flashing a Hollywood-ready set of teeth. "But she says, 'Ryan Gosling looks a bit like you.' That's a nicer way to put it."